EP0074013B1 - Cation emission type halogenated hydrocarbon gas detecting element - Google Patents

Cation emission type halogenated hydrocarbon gas detecting element Download PDF

Info

Publication number
EP0074013B1
EP0074013B1 EP82107746A EP82107746A EP0074013B1 EP 0074013 B1 EP0074013 B1 EP 0074013B1 EP 82107746 A EP82107746 A EP 82107746A EP 82107746 A EP82107746 A EP 82107746A EP 0074013 B1 EP0074013 B1 EP 0074013B1
Authority
EP
European Patent Office
Prior art keywords
detecting element
halogenated hydrocarbon
hydrocarbon gas
detector
emission type
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82107746A
Other languages
German (de)
French (fr)
Other versions
EP0074013A1 (en
Inventor
Masaki Katsura
Mituo 4-403 Suge Jutaku 3484-10 Harata
Osamu Takikawa
Masayuki Shiratori
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of EP0074013A1 publication Critical patent/EP0074013A1/en
Application granted granted Critical
Publication of EP0074013B1 publication Critical patent/EP0074013B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
    • G01N27/626—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using heat to ionise a gas
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T436/00—Chemistry: analytical and immunological testing
    • Y10T436/19—Halogen containing
    • Y10T436/196666—Carbon containing compound [e.g., vinylchloride, etc.]

Definitions

  • This invention relates to a halogenated hydrocarbon gas detecting element of cation emission type.
  • Halogenated hydrocarbon gas has been widely used as refrigerant gas or coolant for electric refrigerators, air conditioners and the like.
  • Halogenated hydrocarbon has a chemical formula wherein one or more of the hydrogen atoms has been replaced by chlorine, fluorine or the like, and typically includes R-12 (CCI z F 2 ), R-22(CHCIF 2 ), etc. These halogenated hydrocarbons are chemically and thermally very stable, harmless to human bodies, and have excellent thermodynamical characteristics when they are used for refrigeration systems.
  • the halogenated hydrocarbon gas mentioned above is alternately compressed and expanded to cause its refrigeration actions.
  • a trace amount of the halogenated hydrocarbon gas may sometimes leak away from compressors, radiators, pipes, etc. If such leaks are left unstopped, efficiency of the refrigeration systems is lowered due to a gradual decrease of the refrigerant gas, with the result of a possible stop of the function of such equipments. Accordingly, severe control is required when such equipments are manufactured in a factory, and it is desirable to periodically check any leak along the pipe systems.
  • the refrigeration systems such as air conditioners for cars and the like, there is a greater possibility of leak due to a shock during drive, and a detector which may simply find out the leaks has long been desired.
  • the air conditioner as mentioned above is heavy in weight, and in addition it is usually fixed at one place or mounted on a car. Therefore, it is impossible to make an inspection thereof by simply turning or overturning it. Moreover, the leaks are usually too small to find out visually or by a magnifier. Further, it is desirable for an element for detecting leaks to be as miniature as possible since the pipe system, etc. is usually of complicated structure. Still further, the detecting end of an element should preferably be as small as possible in diameter since the detecting element traces the pipe or the like to locate a leak. In addition, it is required that a detecting element can be operated by means of a miniature cell or cells in order to make it easy to handle. While the sensitivity of a detector is desirably as high as possible as a matter of course, it is required for it to detect a gas leak of at least 10- 4 cm 3 /sec (25°C, 1 atm).
  • a typical detector a torch, utilizes a kind of flame reaction; it utilizes the phenomenon that the color of a flame changes responding to the chemical reaction of the halogen gas mixed into the flame with a copper metal provided in the flame.
  • this method is simple, it is often accompanied by errors because the presence or absence of leaks is visually judged.
  • the limit of detection according to this method is 10- 2 cm 3 /sec (25°C, 1 atm) at best.
  • a detector which utilizes a high voltage electric discharge.
  • This detector is provided with a pair of electrodes exposed to air with a gap therebetween, to which electrodes is applied a high voltage of several hundred volts for producing an electric discharge at the gap.
  • the discharge stops when halogenated hydrocarbon gas comes into the gap between the electrodes.
  • the leak can be detected by detecting the change of the discharged current, with the detection limit leveled up to 10- 3 cm 3 /sec (25°C, 1 atm) which is sufficient for practical use.
  • this detector which utilizes the electric discharge, is disadvantageous in for example that the discharge is interrupted due to other external causes such as wind or the like even when there is no leak of the halogenated hydrocarbon gases.
  • a detector having sufficiently high sensitivity there has been known a detector called a cation emission type leak detector (see DE-U-7516931).
  • the detector of this type comprises ceramics such as steatite containing Na, K, etc., an ion collector electrode and a heater.
  • the ceramics are kept being heated to a high temperature (e.g. 800°C), to which ceramics there is provided at a predetermined space the ion collector electrode made of a metal. While a high voltage of about 300 V is applied to the space between the ceramics and the ion collector electrode, the halogenated hydrocarbon gas is reacted on the surface of the ceramics due to the high temperature to emit ions of Na, K, etc.
  • the detection limit is not more than 10- s cm 3 /sec (25°C, 1 atm) and thus the detector exhibits very high sensitivity.
  • the detector of this type consumes electric power of as large as 20-30 W because the ceramics must be kept to have a high temperature (about 800°C) as mentioned above, whereby not only a larger size of an apparatus but also a cord for the power source are required.
  • the detector of this type is in contact with an unexpectedly high concentration of the halogenated hydrocarbon gas, the alkaline metals in the vicinity of the surface of the ceramics such as the steatite mentioned above are ionized in large quantities to form a flow of cations which flows to a cathode undesirably, with the result that the alkaline ions in the vicinity of the surface of said ceramics have been consumed.
  • the ceramics because of scantiness of alkaline ions on the surface of the ceramics, a quick response of the detector cannot be expected even if it is brought again into contact with halogenated hydrocarbon gas, and the sufficient detecting sensitivity can not be obtained until the alkaline ions in the ceramics are recovered by having diffused sufficiently in the vicinity of the surface. It is therefore necessary for the ceramics to be heated at a high temperature so that the alkaline ions may readily migrate from the inside of the ceramics to the surface thereof. It is for this reason that the temperature of the element must be kept at 800°C as aforementioned, but nonetheless it shows unavoidable non-sensitivity during a time of several minutes to several ten minutes after having detected halogenated hydrocarbon gas of a high concentration.
  • Such a high temperature further causes disadvantageously a serious breakage or wear of the metallic electrode, and especially a short life time of a heating wire serving also as an anode.
  • the detector of this type which detects the halogenated hydrocarbon gas while consuming the alkaline ions which are finite, has necessarily a limited life time since the whole quantity of the alkaline metal ions contained in the aforesaid ceramics is extremely small.
  • this invention aims to eliminate them and to provide a cation emission type halogenated hydrocarbon gas detecting element which consumes less. electric power, and is of a low price and a high efficiency.
  • ⁇ -AI 2 0 3 which is well known to be a solid electrolyte
  • steatite conventionally used as the cation source
  • Beta-alumina ( ⁇ -Al 2 0 3 ) to be used in this invention is commercially available or may be prepared by a conventional method, e.g., in the following manner:
  • Fig. 1 illustrates a basic construction of a halogenated hydrocarbon gas detecting element of cation emission type.
  • a conventional cation emission type halogenated hydrocarbon gas detecting element having such a basic construction as shown in Fig. 1 was prepared.
  • reference numeral 1 denotes an ion collector electrode made of platinum of a cylindrical shape
  • numeral 2 a heater for heating ceramics containing alkaline ions
  • numeral 3 the ceramics as a cation source, i.e. steatite containing the alkaline ions; these are the basic components constituting the detecting element.
  • a measuring circuit is also shown together in Fig.
  • numeral 4 denotes a high voltage electric source which forms direct current electric field at the space between the ion collector electrode 1 and the heater 2, charging the former with negative and the latter with positive.
  • Numeral 5 denotes an electric source for heating, which may be of either alternating current or direct current.
  • Numeral 6 denotes an ampere meter for measuring the ionic current which corresponds to the quantity of halogenated hydrocarbon gas.
  • a cation emission type halogenated hydrocarbon gas detecting element which has substantially the same basic construction as shown in Fig. 1 and provided with ⁇ -Al 2 O 3 as the cation source 3 in place of steatite in the conventional detecting element.
  • the ⁇ -Al 2 0 3 employed was the one available from Toshiba Ceramics Co., Ltd. and having composition of 1.2 Na 2 O . 11 Al 2 O 3 containing 6.2 wt% of Na. Comparing the efficiency of the detecting element of this invention with that of the above-mentioned conventional one, the results were as follows:
  • the ⁇ -Al 2 O 3 used in this invention having in nature relatively higher mobility of Na + ions even at a room temperature, showed enhanced mobility of the Na + ions. Accordingly, having constructed such detecting element as shown in Fig. 1 by using the ⁇ -Al 2 O 3 , a lower temperature of about 300-600°C was employable as a matter of fact.
  • the cation source which is smaller in size than the conventional one, i.e. the one smaller in the surface area of the cylindrical body corresponding to the numeral 3 in Fig. 1, was sufficiently suited to a practical use; in fact, ⁇ -Al 2 O 3 having the surface area which was smaller by a factor of about 1/10 was operable as the cation source of the detecting element. Therefore, the detecting element according to this invention was able to be miniaturized to about 1/3 size by employing the (3-AI 2 0 3 . In addition thereto, the electric power to be consumed by the heater 2 was as small as not more than 1/10 of the power consumed by the conventional detecting element, because it was possible for the detecting element of this invention to work at the aforementioned lower temperature.
  • the detecting element of this invention was further advantageous in that it was not the case with the invention that the element had no sensitivity for a long time as in the case of the conventional type after it came into contact with the gas of a high concentration, because the migration of Na + ions in the ⁇ -Al 2 O 3 was performed swiftly; the sensitivity of the detector of this invention was recovered in about five seconds even after it was exposed to a 100% concentration of the halogenated hydrocarbon gas for about ten seconds.
  • Example 1 Prepared was a detecting element according to this invention in the same manner as in Example 1 except that the ion collector electrode made of platinum was replaced by one made of nickel to compare its performance with that of the conventional detecting element. Substantially the same results as in the case of Example 1 were obtained.
  • the conventional detecting element whose temperature reaches as high as 800°C, employs platinum or the like as the material for the ion collector electrode because otherwise it seriously shows change in its characteristics or is damaged by the oxidation of the heating wire and the collector electrode.
  • platinum is limited in resource and high in price, so that the price of the detecting element has been raised, and there has been a problem in using it widely.
  • the detecting element for the detecting element according to this invention, ordinary metals including Ni and the like can be used with substantially no problem because of its lower operating temperature. Besides, since it can be miniaturized, wide use thereof can be expected. Further, it becomes feasible that the element is operable with cells because the electric power to be consumed by it is as small as 2 to 3 W, and therefore it has become possible to provide a detector which is easy to use even at a place distant from an electric source or at a complicated place, while the conventional detector has required an electric source of AC 100 V. These advantages result from the employment of (3-AI 2 0 3 as the alkaline ionic source. As a result, there can be provided a detector which is not only superior in the detecting efficiency to that of the conventional detector, but also very easy to handle practically.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Combustion & Propulsion (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
  • Examining Or Testing Airtightness (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Description

  • This invention relates to a halogenated hydrocarbon gas detecting element of cation emission type.
  • Halogenated hydrocarbon gas has been widely used as refrigerant gas or coolant for electric refrigerators, air conditioners and the like. Halogenated hydrocarbon has a chemical formula wherein one or more of the hydrogen atoms has been replaced by chlorine, fluorine or the like, and typically includes R-12 (CCIzF2), R-22(CHCIF2), etc. These halogenated hydrocarbons are chemically and thermally very stable, harmless to human bodies, and have excellent thermodynamical characteristics when they are used for refrigeration systems.
  • In the refrigeration systems, the halogenated hydrocarbon gas mentioned above is alternately compressed and expanded to cause its refrigeration actions. At this time, a trace amount of the halogenated hydrocarbon gas may sometimes leak away from compressors, radiators, pipes, etc. If such leaks are left unstopped, efficiency of the refrigeration systems is lowered due to a gradual decrease of the refrigerant gas, with the result of a possible stop of the function of such equipments. Accordingly, severe control is required when such equipments are manufactured in a factory, and it is desirable to periodically check any leak along the pipe systems. Especially, in the refrigeration systems such as air conditioners for cars and the like, there is a greater possibility of leak due to a shock during drive, and a detector which may simply find out the leaks has long been desired.
  • Generally, the air conditioner as mentioned above is heavy in weight, and in addition it is usually fixed at one place or mounted on a car. Therefore, it is impossible to make an inspection thereof by simply turning or overturning it. Moreover, the leaks are usually too small to find out visually or by a magnifier. Further, it is desirable for an element for detecting leaks to be as miniature as possible since the pipe system, etc. is usually of complicated structure. Still further, the detecting end of an element should preferably be as small as possible in diameter since the detecting element traces the pipe or the like to locate a leak. In addition, it is required that a detecting element can be operated by means of a miniature cell or cells in order to make it easy to handle. While the sensitivity of a detector is desirably as high as possible as a matter of course, it is required for it to detect a gas leak of at least 10-4 cm3/sec (25°C, 1 atm).
  • There has been proposed a number of halogenated hydrocarbon gas detectors, some examples of which are being explained below:
  • A typical detector, a torch, utilizes a kind of flame reaction; it utilizes the phenomenon that the color of a flame changes responding to the chemical reaction of the halogen gas mixed into the flame with a copper metal provided in the flame. Although this method is simple, it is often accompanied by errors because the presence or absence of leaks is visually judged. Moreover, the limit of detection according to this method is 10-2 cm3/sec (25°C, 1 atm) at best.
  • Further, there has been proposed a detector which utilizes a high voltage electric discharge. This detector is provided with a pair of electrodes exposed to air with a gap therebetween, to which electrodes is applied a high voltage of several hundred volts for producing an electric discharge at the gap. The discharge stops when halogenated hydrocarbon gas comes into the gap between the electrodes. As a result, the leak can be detected by detecting the change of the discharged current, with the detection limit leveled up to 10-3 cm3/sec (25°C, 1 atm) which is sufficient for practical use. However, this detector, which utilizes the electric discharge, is disadvantageous in for example that the discharge is interrupted due to other external causes such as wind or the like even when there is no leak of the halogenated hydrocarbon gases.
  • On the other hand, as a detector having sufficiently high sensitivity, there has been known a detector called a cation emission type leak detector (see DE-U-7516931). The detector of this type comprises ceramics such as steatite containing Na, K, etc., an ion collector electrode and a heater. The ceramics are kept being heated to a high temperature (e.g. 800°C), to which ceramics there is provided at a predetermined space the ion collector electrode made of a metal. While a high voltage of about 300 V is applied to the space between the ceramics and the ion collector electrode, the halogenated hydrocarbon gas is reacted on the surface of the ceramics due to the high temperature to emit ions of Na, K, etc. contained in the ceramics, which ions are attracted to and captured by the metallic electrode with the aid of the high voltage. As the result, the leak can be detected by detecting ionic current thus generated. According to this detector, the detection limit is not more than 10-s cm3/sec (25°C, 1 atm) and thus the detector exhibits very high sensitivity.
  • However, the detector of this type consumes electric power of as large as 20-30 W because the ceramics must be kept to have a high temperature (about 800°C) as mentioned above, whereby not only a larger size of an apparatus but also a cord for the power source are required. Moreover, when the detector of this type is in contact with an unexpectedly high concentration of the halogenated hydrocarbon gas, the alkaline metals in the vicinity of the surface of the ceramics such as the steatite mentioned above are ionized in large quantities to form a flow of cations which flows to a cathode undesirably, with the result that the alkaline ions in the vicinity of the surface of said ceramics have been consumed. Accordingly, because of scantiness of alkaline ions on the surface of the ceramics, a quick response of the detector cannot be expected even if it is brought again into contact with halogenated hydrocarbon gas, and the sufficient detecting sensitivity can not be obtained until the alkaline ions in the ceramics are recovered by having diffused sufficiently in the vicinity of the surface. It is therefore necessary for the ceramics to be heated at a high temperature so that the alkaline ions may readily migrate from the inside of the ceramics to the surface thereof. It is for this reason that the temperature of the element must be kept at 800°C as aforementioned, but nonetheless it shows unavoidable non-sensitivity during a time of several minutes to several ten minutes after having detected halogenated hydrocarbon gas of a high concentration. Such a high temperature further causes disadvantageously a serious breakage or wear of the metallic electrode, and especially a short life time of a heating wire serving also as an anode. In addition, the detector of this type, which detects the halogenated hydrocarbon gas while consuming the alkaline ions which are finite, has necessarily a limited life time since the whole quantity of the alkaline metal ions contained in the aforesaid ceramics is extremely small.
  • In view of the drawbacks in the conventional detecting elements as mentioned above, this invention aims to eliminate them and to provide a cation emission type halogenated hydrocarbon gas detecting element which consumes less. electric power, and is of a low price and a high efficiency.
  • According to the invention, this problem is solved by means of the detecting element defined in Claim 1.
  • By employing α-AI203, which is well known to be a solid electrolyte, in place of the steatite conventionally used as the cation source, it becomes possible to miniaturize the size of the element to a great extent, and improve the durability of the element as it can work at a lower temperature. Further, according to this invention, it is unnecessary to limit the material for the ion collector electrode used as an opposite pole to a particular material such as platinum which has been required so in the conventional detector, and it is possible to use an ordinary material such as Ni.
  • Beta-alumina (β-Al203) to be used in this invention is commercially available or may be prepared by a conventional method, e.g., in the following manner:
    • Powders of alpha-alumina (a-A1203) and sodium monoxide (Na20) or sodium hydrogencarbonate (NaHC03) are mixed in predetermined amounts and calcined at 1250°C, to which is added an organic binder such as a 2 wt% solution of PVA. A mixture thus obtained is pressed under pressure of 1 ton/cm2, followed by removing the organic solvent at 800°C in air and firing the resultant product at 1600 to 1700°C for two hours in a Pt or MgO crucible, thereby obtaining a beta-alumina (β-Al203).
  • This invention will be described below in more detail by giving examples of its embodiments and comparing them with a conventional detector, with reference to the accompanying drawing (Fig. 1):
    • Example 1
  • Fig. 1 illustrates a basic construction of a halogenated hydrocarbon gas detecting element of cation emission type. For comparison a conventional cation emission type halogenated hydrocarbon gas detecting element having such a basic construction as shown in Fig. 1 was prepared. In Fig. 1, reference numeral 1 denotes an ion collector electrode made of platinum of a cylindrical shape, numeral 2 a heater for heating ceramics containing alkaline ions, and numeral 3 the ceramics as a cation source, i.e. steatite containing the alkaline ions; these are the basic components constituting the detecting element. A measuring circuit is also shown together in Fig. 1 by illustrating its principle; numeral 4 denotes a high voltage electric source which forms direct current electric field at the space between the ion collector electrode 1 and the heater 2, charging the former with negative and the latter with positive. Numeral 5 denotes an electric source for heating, which may be of either alternating current or direct current. Numeral 6 denotes an ampere meter for measuring the ionic current which corresponds to the quantity of halogenated hydrocarbon gas.
  • Also prepared was a cation emission type halogenated hydrocarbon gas detecting element according to the invention, which has substantially the same basic construction as shown in Fig. 1 and provided with β-Al2O3 as the cation source 3 in place of steatite in the conventional detecting element. The β-Al203 employed was the one available from Toshiba Ceramics Co., Ltd. and having composition of 1.2 Na2O . 11 Al2O3 containing 6.2 wt% of Na. Comparing the efficiency of the detecting element of this invention with that of the above-mentioned conventional one, the results were as follows:
  • In the case of the conventional detecting element, which was provided as the cation source 3 in Fig. 1 with the ceramics of steatite containing alkaline ions, it was necessary to heat said steatite to 800°C or higher in order to promote emission of a sufficient quantity of the alkaline ions.
  • In contrast thereto, the β-Al2O3 used in this invention, having in nature relatively higher mobility of Na+ ions even at a room temperature, showed enhanced mobility of the Na+ ions. Accordingly, having constructed such detecting element as shown in Fig. 1 by using the β-Al2O3, a lower temperature of about 300-600°C was employable as a matter of fact.
  • Since the ionic concentration of the alkaline ions present at the surface of the α-AI203 solid electrolyte of this invention is higher than that of the conventional steatite, the cation source which is smaller in size than the conventional one, i.e. the one smaller in the surface area of the cylindrical body corresponding to the numeral 3 in Fig. 1, was sufficiently suited to a practical use; in fact, β-Al2O3 having the surface area which was smaller by a factor of about 1/10 was operable as the cation source of the detecting element. Therefore, the detecting element according to this invention was able to be miniaturized to about 1/3 size by employing the (3-AI203. In addition thereto, the electric power to be consumed by the heater 2 was as small as not more than 1/10 of the power consumed by the conventional detecting element, because it was possible for the detecting element of this invention to work at the aforementioned lower temperature.
  • The detecting element of this invention was further advantageous in that it was not the case with the invention that the element had no sensitivity for a long time as in the case of the conventional type after it came into contact with the gas of a high concentration, because the migration of Na+ ions in the β-Al2O3 was performed swiftly; the sensitivity of the detector of this invention was recovered in about five seconds even after it was exposed to a 100% concentration of the halogenated hydrocarbon gas for about ten seconds.
    • Example 2
  • Prepared was a detecting element according to this invention in the same manner as in Example 1 except that the ion collector electrode made of platinum was replaced by one made of nickel to compare its performance with that of the conventional detecting element. Substantially the same results as in the case of Example 1 were obtained.
  • As described in the foregoing, the conventional detecting element, whose temperature reaches as high as 800°C, employs platinum or the like as the material for the ion collector electrode because otherwise it seriously shows change in its characteristics or is damaged by the oxidation of the heating wire and the collector electrode. However, it is well known that the platinum is limited in resource and high in price, so that the price of the detecting element has been raised, and there has been a problem in using it widely.
  • Whereas, for the detecting element according to this invention, ordinary metals including Ni and the like can be used with substantially no problem because of its lower operating temperature. Besides, since it can be miniaturized, wide use thereof can be expected. Further, it becomes feasible that the element is operable with cells because the electric power to be consumed by it is as small as 2 to 3 W, and therefore it has become possible to provide a detector which is easy to use even at a place distant from an electric source or at a complicated place, while the conventional detector has required an electric source of AC 100 V. These advantages result from the employment of (3-AI203 as the alkaline ionic source. As a result, there can be provided a detector which is not only superior in the detecting efficiency to that of the conventional detector, but also very easy to handle practically.

Claims (2)

1. A cation emission type halogenated hydrocarbon gas detecting element comprising a cation source consisting of a ceramic member (3) which releases alkali metal ions when heated in the presence of a halogenated hydrocarbon gas, a heating means (2) for said ceramic member and an ion collector electrode (1), the detecting element being characterised in that said ceramic member (3) comprises (3-AI203.
2. The detecting element according to Claim 1, wherein said ion collector electrode (1) is made of nickel.
EP82107746A 1981-08-31 1982-08-24 Cation emission type halogenated hydrocarbon gas detecting element Expired EP0074013B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP56135414A JPS5837556A (en) 1981-08-31 1981-08-31 Cation discharge type halogenated hydrocarbon sensor
JP135414/81 1981-08-31

Publications (2)

Publication Number Publication Date
EP0074013A1 EP0074013A1 (en) 1983-03-16
EP0074013B1 true EP0074013B1 (en) 1985-11-21

Family

ID=15151165

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82107746A Expired EP0074013B1 (en) 1981-08-31 1982-08-24 Cation emission type halogenated hydrocarbon gas detecting element

Country Status (6)

Country Link
US (1) US4499054A (en)
EP (1) EP0074013B1 (en)
JP (1) JPS5837556A (en)
KR (1) KR860000472B1 (en)
AU (1) AU531552B2 (en)
DE (1) DE3267604D1 (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62503186A (en) * 1985-06-27 1987-12-17 ウクラインスキ　ゴスダルストベンニ　プロエクトニイ　ナウチノ−イススレドバテルスキ　インスティテュト　コミュナルニフ　ソ−ルゼニ　ゴロドフ“ウクロコミュニイプロエクト” Surface ionization sensor for halogen gas leak detector
SU1698727A1 (en) * 1988-06-02 1991-12-15 Институт электроники им.У.А.Арифова Surface ionization detector for analysis of gas mixtures
US4928033A (en) * 1988-11-15 1990-05-22 Environmental Technologies Group, Inc. Thermionic ionization source
US5293130A (en) * 1991-07-02 1994-03-08 Martin Marietta Energy Systems, Inc. Proportional counter device for detecting electronegative species in an air sample
US5238650A (en) * 1991-09-13 1993-08-24 W. R. Grace & Co.-Conn. Electrode feed through
US5397552A (en) * 1992-02-27 1995-03-14 Process Technologies, Inc. Method and apparatus for use in photochemically oxidizing gaseous organic compounds
US5260036A (en) * 1992-02-27 1993-11-09 Process Technologies, Inc. Method and apparatus for use in photochemically oxidizing gaseous halogenated organic compounds
US5601184A (en) * 1995-09-29 1997-02-11 Process Technologies, Inc. Method and apparatus for use in photochemically oxidizing gaseous volatile or semi-volatile organic compounds
WO2003050511A1 (en) * 2001-12-13 2003-06-19 The University Of Wyoming Research Corporation Doing Business As Western Research Institute Volatile organic compound sensor system

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2742585A (en) * 1952-08-22 1956-04-17 Gen Electric Electrical vapor detector
BE534288A (en) * 1953-12-24
GB1447364A (en) * 1972-11-24 1976-08-25 Defence Secretaryof State For Oxygen sensors
US4166009A (en) * 1974-07-03 1979-08-28 National Research Development Corporation Method for detecting elements
DE7516931U (en) * 1974-07-18 1976-02-05 Balzers Hochvakuum Gmbh, 6201 Nordenstadt Device for the detection of gases and vapors.
US3972480A (en) * 1975-05-29 1976-08-03 General Electric Company Method of preparing a suspension of additive-free beta-alumina particles
GB1603496A (en) * 1978-05-16 1981-11-25 Atomic Energy Authority Uk Measuring devices and apparatus
FR2426905A2 (en) * 1978-05-22 1979-12-21 Auergesellschaft Gmbh Continuous automatic determn. of vinyl chloride in gas streams - by thermo-hydrolytic decomposition and determn. of the hydrogen chloride formed

Also Published As

Publication number Publication date
KR860000472B1 (en) 1986-04-28
JPS5837556A (en) 1983-03-04
EP0074013A1 (en) 1983-03-16
US4499054A (en) 1985-02-12
AU531552B2 (en) 1983-08-25
KR840001337A (en) 1984-04-30
DE3267604D1 (en) 1986-01-02
AU8741582A (en) 1983-03-10
JPS6342741B2 (en) 1988-08-25

Similar Documents

Publication Publication Date Title
KR0169126B1 (en) Miniature gas sensor
US3751968A (en) Solid state sensor
US5284569A (en) Miniature gas sensor
CA2507428C (en) Hydrogen gas sensor
EP0074013B1 (en) Cation emission type halogenated hydrocarbon gas detecting element
WO1991006692A1 (en) Ceramic solid electrolyte based electrochemical oxygen concentrator cell and method of fabrication
Rickert Solid ionic conductors: principles and applications
US20200166470A1 (en) Method and system for multi-sensor gas detection
EP0075835A2 (en) Gas leak detector
Lazennec et al. Factors Influencing the Lifetime of Pure Beta‐Alumina Electrolyte
US3751969A (en) Detection system
US4902402A (en) Chloride containing solid electrolyte gas sensing apparatus
WO2022079925A1 (en) Fuel cell hydrogen gas concentration sensor
CN110380072B (en) Composite flow inhibitor for lithium-based thermal battery electrolyte, electrolyte diaphragm material, lithium-based thermal battery and preparation method of composite flow inhibitor
EP0221381A2 (en) Electrochemical gas sensor
GB2117121A (en) Electrochemical chlorine sensor
US3437524A (en) Solid electrolyte alkali metal voltaic cell
Fujiwara et al. Effect of Electrochemical Polarization on the Emission of O− Ions from the Surface of YSZ
RU1801204C (en) Electrochemical transducer of carbon dioxide
Weber Applications of beta alumina in the energy field
GB2517902A (en) Method and apparatus for sensing molecular gases
JPH0763722A (en) Nitrogen oxide sensor
US4214967A (en) Technique for reducing solid electrolyte cell drift
Berk et al. Carbon electrochemistry in alkaline systems
JACOB et al. A Sensor for HS or S, Based on 8-Alumina

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE GB NL

17P Request for examination filed

Effective date: 19830801

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: KABUSHIKI KAISHA TOSHIBA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE GB NL

REF Corresponds to:

Ref document number: 3267604

Country of ref document: DE

Date of ref document: 19860102

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: 746

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19920814

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19920824

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19920831

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19930824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19940301

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19930824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19940503